Type head shifting apparatus

ABSTRACT

A type head has two substantially hemispherical surfaces, with lower case and upper case types, respectively, arranged in circular rows. The lower case surface is normally in an operative position for printing. The shaft of the type head is normally connected with setting means for selecting a type for printing, but is turned by shifting means under the control of a shift key to turn the type head 180* to place the upper case surface in a position for printing, and to turn the type head 180* back to the normal position after a desired type has been selected by the setting means, and printed. A clutch is operated by the shift key to connect either the setting means, or the shifting means, with the motor driven drive means of the typewriter.

Waited States Patent [1 1 van der Werif et al.

l l TYPE HEAD SHIFTING APPARATUS [75 Inventors: Chien van der Werff, (arolinensiek Dieter Hellebrandt, Wilhelmshaven. both of Germany [73] Assignee: Olympia Werke A G,

Wilhelmshaven, Germany [22] Filed: Feb. 26, 1971 [21] Appl. No.: 119,307

[ June 12, 1973 Cralle et al. 197/16 Knudsen et al 197/16 X [57] ABSTRACT A type head has two substantially hemispherical surfaces, with lower case and upper case types, respectively, arranged in circular rows. The lower case surface is normally in an operative position for printing The shaft of the type head is normally connected with setting means for selecting a type for printing, but is turned by shifting means under the control of a shift key to turn the type head 180 to place the upper case surface in a position for printing, and to turn the type head 180 back to the normal position after a desired type has been selected by the setting means, and printed. A clutch is operated by the shift key to connect either the setting means, or the shifting means, with the motor driven drive means of the typewriter.

12 Claims, 6 Drawing Figures PATENIED 21975 3. 738.47 1

saw 1 or a IN VE N TORS Mm #09:: were: fiewsgnwuf PATENTEB 2 SHEET 3 BF 3 INVA'NTOR 6/110 MM 9 were: uwes w' 65- I fl 1 I I w TYPE HEAD SHIFTING APPARATUS BACKGROUND OF THE INVENTION The German Pat. No. 1,078,591 andthe U.S. Pat. No. 2,9 I 9,002, disclose shifting devices for ball-shaped typeheads whose surface is divided into two hermispherical halves which respectively carry the lower case types and the upper case types in the same arrangement. When a shift key is operated, the type head performs a turning movement of 180 so that the upper case type can be selected by operation of the setting means in the same manner as the lower case types in the normal position of the type heads.

The shifting of the type head is effected by a steel band, one end of which is connected with the type head carriage, while the other end of the same is connected to a disk secured to the type head shaft. A spiral spring acts on the disk to continuously tension the steel band. This kind of shifting is not very well suited for highspeed operations, since the type head moves, when the shift key is operated, beyond the desired position due to inertia. Printing can take place only after a certain period of time has elapsed, and the type head has come to a complete standstill. Furthermore, the time required for turning the type head to the normal lower case position, is dependent on the force of the return spring.

SUMMARY OF THE INVENTION It is one object of the invention to overcome the disadvantages of the prior art setting devices, and to provide a setting device for a type head operating at high speed, and accurately placing the type head in the upper case and lower case positions.

Another object of the invention is to return the type head between the upper case and the lower case position by cyclically operating means which cause a move.- ment of the type head 180 in accordance with a sine function so that the type head rotates at a reduced speed when stopped in the upper case position or lower case position.

With these objects in view, the shaft of the type head has a first coupling half which is positively coupled with a second coupling half for turning movement between the two angularly spaced positions thereof. The shifting means includes cyclically operating means which move the type head at a first gradually increase and then at a gradual decreased speed, in accordance with a sine function, to the respective upper case and lower case positions.

An embodiment of the invention comprises a type head and a type head shaft mounted on support means, such as a slide or carriage, for rotation about a type head axis. The type head has an annular surface concentric with the axis, and composed of a first surface portion with first character types, and a second surface portion with second character types, preferably for .representing upper case characters, and lower case a first rotary output shaft. The term positive is used in the present application to define a form-locked engagement or connection without transmission of force by springs.

Setting means are also driven by the drive means and have a second output shaft.

Clutch means are controlled by the cyclically operating means to move between a first coupling position for coupling the first output shaft with a type head shaft for rotating the type head from any one of the angular positions to the other angular position, and a second coupling position for coupling the second rotary output shaft for rotating the type head until a selected type on the surface portion in the operative position, is placed by the setting means in a printing position.

In accordance with the invention, the type head is ac celerated and decelerated in accordance with a sine function, so that an inertia movement of the type head beyond the desired upper case or lower case position, is not possible, even if the type head is driven at high speed.

Due to the compact construction of the embodiments of the invention, the type head shifting and setting apparatus can be constructed as a unit, which can be easily controlled by interposer code elements operated by keys.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary perspective view illustrating a type head setting and shifting apparatus;

FIG. 2 is an axial sectional view of the type head shifting apparatus shown in FIG. 1;

FIG. 3 is a fragmentary perspective, partly exploded view, illustrating the embodiment of FIG. 2;

FIG. 4 is a horizontal sectional view of the apparatus shown in FIGS. 1 and 3, illustrating particularly a type head shifting apparatus of the embodiment of FIGS. 1-3;

FIG. 5 is a partly schematic view, illustrating a cyclically operating means controlled by a shift key for shifting the type head of the embodiment of FIGS. 1 to 4 between angular positions in which lower case types and upper case types, respectively, are operative and located opposite the printing surface and FIG. 5a is a perspective exploded view illustrating a transmission transforming rotary movement at constant speed into sinusoidal movement.

DESCRIPTION OF THE PREFERRED EMBODIMENT spherical surface halves 7e and 7E, each of which extends 180. The surface half 7e contains only lower case character types, and the surface half 7E contains only upper case character types. Corresponding characters, such as a and A are located at corresponding points of the two surface halves 7e and 7E.

In the normal position of type head 7, the hemispherical surface half 7e with lower case character types, confronts the platen 4, so that by movement of slide 5 toward platen 4, an imprint of a selected lower case character can be made. When the type head 7 is turned 180 in a manner which will be explained later, the respective upper case character type can be selected for printing, and placed directly opposite the platen 4. The setting apparatus operation for setting the type head 7 to a position in which a selected type is operative, is partly shown in FIGS. 1 and 3, but is not an object of the present invention, and disclosed in my co-pending application TYPE HEAD SETTING APPARATUS, Ser. No. 118,811 filed Feb. 25, 1971.

The type head shaft 9 is supported for rotation on the slide 1 1, as particularly shown in FIG. 2 in which a part of slide 11 is shown broken off.

The lower end of type head shaft 9 carries a coupling pin 12 which is normally located in a cutout 13a of a coupling member 13 which is axially movable on shaft 9 and urged by a spring 19 to a position in which cutout 13a engages coupling pin 12. A gear 15 is secured to coupling part 13, and can move with the same in axial direction. Coupling part 13 and gear 15, which is the output means of the setting means, which are not an object of the present invention, is connected with shaft 9 for rotation so that any type of the type head 7 can be selected by turning the type head 7 to a position in which the respective type is located opposite platen 4, and is printed when shaft 9 and type head 7 are moved with slide 11 towards the platen 4.

A shaft 68, mounted in a portion 47 of carriage 5, has a coupling part 17 with a coupling cutout 18, also cooperating with coupling pin 12. Coupling part 17 forms an annular shoulder 17a which is slidingly engaged by a pair of pins 55a diametrically arranged on a pair of prongs 55b of the forked end of a cam follower lever 55. Lever 55 has a follower portion 57 cooperating with rotary cam means 53, best seen in FIGS. 2 and 3.

The lower end of shaft 68 cooperates with a spring 69 which urges shaft 68 together with coupling part 17 downward so that cam follower lever 55 with cam follower 57 is urged into engagement with cam 53. Shaft 68 has an elongated pinion portion 67.

When shaft 67 is moved upward by operation of the cam follower means 55,57, as will be described hereinafter in detail, shaft 68 moves against the action of spring 69 upward to a position in which the coupling part 1 7 displaces coupling part 13 on shaft 9 until coupling pin 13 is no longer located in coupling cutout 13a, but is located in coupling cutout 18 of coupling part 17, so that the rotational movement of the type head means 7,9, is no longer derived from gear 15, but from the gear 67. However, in the normal position of the typewriter, spring 69 holds coupling part 17 in the inoperative position as shown in FIG. 2, while spring 19 holds coupling part 13 with setting gear 15, in the coupled position shown in FIG. 3, so that by operation of the conventional typewriter keys, not shown, gear setting means of the typewriter turn output gear 15 together with type head shaft 9 and type head 7 to a position in which a selected type is located opposite the platen 4. If type head 7 is in a position turned 180, so that the hemispherical surface 7E with the upper case types is located opposite the platen 4, an upper case character is selected for printing, and it will be understood that upper and lower case characters appearing in the usual manner on the same typewriter key, are placed in corresponding positions on surfaces 7e and 7E of the type head 7.

As best seen in FIGS. 3 and 4, a drive gear 23 is mounted on carriage 5 and has a central opening engaging a non-circular continuously driven drive shaft 3 so that gear 23 is rotated irrespective of the displacement of carriage 5 with type head- 7 along platen 4. Gear 23 drives another gear 25 which meshes with the gear 27 connected by shaft 29 with a gear 31 meshing with a gear 33.

FIG. 4 shows parts of the type head setting apparatus of my above-mentioned co-pending application, without reference numerals, which have been applied in FIG. 4 and FIG. 3 only to parts which are relevant to the present invention. A setting gear segment 21 meshes with output gear 15 of the setting means.

The drive gear 33 is fixedly secured to a cylindrical bushing 35 which is rotatable on a shaft 41. Shaft 41 is fixedly secured to another cylindrical bushing 43 which can be coupled by a coil spring 39 with a cylindrical bushing 35. Pin 43a secures bushing 43 to shaft 41. Parts 35, 39, 43 form a shift clutch 60.

Clutch spring 39, which extends over the cylindrical surfaces of bushings 35 and 43, is normally-held by a member 36, to which one endof a spring 39 is secured, in a spread condition so that shaft 41 is not coupled with drive gear 33 and bushing 35. A projection 37 of part 36 is held by a latch 83 whose end portion 85 engages projection 37, so that the spring 39 is spread and has a larger diameter than the cylindrical surfaces of bushings 35 and 43.

Referring now to FIG. 5, a shift key means includes the shift key 73 and a key lever 71 mounted on a pivot 75 for angular movement, and normally abutting the schematically shown stop 93 of the typewriter frame due to the action of a spring 91. Lever 71 has a actuating projection 77 near a pivot pin 75 which cooperates with a normally open switch 79. The arrangement is such that during depressure of shift key 73, projection 77 engages one contact of switch 79, and momentarily closes switch 79 before assuming the position 7 7a shown in chain lines. When switch 79 is closed, an electromagnet 81 is energized and its armature turns a latch 83 against the action of the spring 87 about a schematically shown pivot 84 to a position in which the projection 37 of member 36 is released so that the spring 39 can turn to a position actuating clutch 60 and connecting the cylindrical bushings 35 and 43 for rotation, so that shaft 41 is connected with the rotary drive gear 33 and bushing 35, and is rotated to turn a pinion 51 secured thereto, and shown in FIGS. 2, 3 and 4.

When shift key 73 is released and turned by spring 9 towards its initial normal lower case position, projection 77 again passes over a contact of switch 79 and shortly closes the same so that electromagnet 81 oper- .ates latch 83, 85 to again release projection 37 of A rotary member 49 has a flange with a circular inner gear 49a meshing with the pinion 51, and turns in bearing surface 47a.

Rotary member 49. has diametrically arranged cam means 53 which are engaged by the cam follower means 55, 57 due to theaction of spring 69, as explained above. Cam follower lever 55 is mounted on a pivot means 56 secured to carriage 5, as best seen in FIG. 2.

A pin 59 is secured to the member 49, and engages a slot 63 in a rack member 61, best seen in FIGS. 2 and 5. Rack member 61.is mounted in guide means 47b formed in the support portion 47 of carriage 5.

During rotation of rotary member 49 with pin 59, the movement of the positive transmission 59, forces the rack member 61 with rack 65 to move in a rectilinear movement at a speed varying in accordance with the sine function.

Rack bar 65 meshes with the gear portion 67 of shaft 68, which constitutes the output means of the setting means 41,60,51,49,59,6l,63,65.

OPERATION Assuming that the type head 7 is in the normal position in which the surface half 7e with lower case character confronts platen 4, shift clutch 60 is disengaged since shift key means 73,71,77 does not close switch 79. Consequently, output means 67,68, is not rotated, and spring 69 urges the same with coupling part 17 to the position of FIG. 2 inwhich coupling cutout 18 does not engage coupling pin 13. on type head shaft 9. Since coupling pin 12 is located in cutout 13a due to the action of spring 19, setting gear 15 can be rotated under the control of the typewriter keys to place a selected lower case type on the hemispherical surface 7e in the printing position opposite platen 4.

1f the use of an upper case character is desired, shift key 73 is operated, and moves through an actuating position, engaging and closing switch 79 to a depressed position, in which it may be manually held. During closing of switch 79, latch 83,85 is operated by electromagnet means 81, projecting 37 is released, and shift clutch 60 is engaged so that the rotary transmission member 49 with the pin 59 rotates, causing movement of rack member 61 in accordance with a sine function. Since rack 65 meshes with the output gear 67, the same is rotated an angle of 180 at a speed which follows the same sine function.

However, before output gear 67 of the shifting means is driven, the rotary member 49 turns to a position in which its cam means 53 turns cam follower means 55,57,55b,55a in counterclockwise direction so that coupling part 17 is raised, displaces the coupling part 13, and assumes a position in which coupling pin 12 is located in coupling cutout 18.

Consequently, the angular movement of the output means 67,68, in accordance with the sine function, is transmitted to the type head shaft 9, and to the type head, so that the same is turned 180 while it is gradually accelerated and decelerated. Due to the deceleration before arriving at the new position in which the hemispherical surface 7E confronts platen 4, the type head stops exactly in the correct upper case position, without being driven by inertia beyond the correct position.

The coupling operation of the clutch means 12,38,13,17,18 must be carried out very quickly so that the output means 67,68 of the shifting means are coupled with type head shaft 9, and the output gear 15 of the setting means is disengaged from type head shaft 9 before the angular movement of type head 7 through under the control of the output means 67,68 of the shifting means.

The hemispherical surface 7E, and the upper case types are now in operative position confronting platen Since projection 77 of shift key 73,71 only shortly passes switch 79, the depressed shift key 13,71 permits return of switch 79 to the open position, deenergization of electromagnet 81, and operation of latch 83,85 by spring 87 into a position engaging projection 37 of shift clutch part'36, whereby the shift clutch 60 is again disengaged. Output shaft 67,68 stops, and the low portion 53a between two cam means 53 is engaged by cam follower 57 of cam follower lever 55, so that spring 69 retracts output means 67, 68 and coupling part 17, permitting coupling part 13 to be moved by spring 19 to a coupled position in which cutout 13a engages pin 13, and the setting means, including output gear 15, can be operated in a manner which is not an object of the invention, to place a selected type in the printing position by rotating the type head means 7,9.

As usual, the actuation of a typewriter key corresponding to the selected upper case character type, is carired out while shift key 73,71 is held fully depressed.

When shift key 73,71 is again released, projection 77 passes shortly over switch 79 and closes the same again so that electromagnet means 81 actuates latch 83,85, as during the initial actuation of shift key 73,71, and places shift clutch 60 in the engaged condition so that rotary member 49 is turned half a revolution, and pin 59 in slot 63 positively causes a rectilinear movement of rack bar 61 whereby rack 65, meshing with output gear 67 of the shifting means, is turned in accordance with the sine function, while cam follower means 55,57 are operated by the second cam means 53 to couple coupling part 17 with pin 12, while disconnecting coupling part 13 from the same, so that the type head is turned in the opposite direction 180 to the lower case position.

The transmission ratio between the pinion 59 and the inner gear 49a of rotary member 49 is 2:1, which means that the shift clutch 60 must be twice actuated while the rotary member 49 of the cyclically operating means 49a,49,57,59,63,61,65 performs one complete revolution.

It is possible to use the apparatus of the present invention in a typewriter having a type segment with type bars, and to shift the type segment between upper case position and lower case position in the manner described for the type head 7.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of case shifting apparatus differing from the types described above.

While the invention has been illustrated and described as embodied in a type head shifting apparatus for rotating the type head 180 between a lower case position and an upper case position before setting means select one of the types of the type head for printing, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

1. Type head shifting apparatus comprising a support means; type head means mounted on said support means and including a type head and a type head shaft mounted on said support means for rotation about an axis, said type head having an annular surface concentrio with said axis and having a first surface portion with first character types and a second surface portion with second character types, .and first and second character types being disposed along at least one circular line concentric with said axis, said type head means having first and second angular positions in which said first and second surface portions, respectively, are in operative positions for printing; drive means; shifting means including a shift key means, and cyclically operating means connectable with said drive means under the control of said shift key means, said cyclically operating means including a rotary member having an excentric pin, and having a first rotary output means including an output gear; shift clutch means operable by said shift key means to connect said drive means with said rotary member for rotation so that said pin moves along along a circular path; a rack member guided for straight movement and having a slot receiving said pin so that said rack member is accelerated and decelerated in accordance with a sine function during rotation of said rotary member by said drive means and by said engaged shift clutch, said output gear meshing with said rack member; setting means driven by said drive means and having a second output means; and clutch means controlled by said cyclically operating means to move between a first coupling position for coupling said first rotary output means with said type head shaft for rotating said type head from any one of said angular positions to the other angular position, and a second coupling position for coupling said second rotary output means with said type head shaft for rotating said type head until a selected type on the surface portion in said operative position is placed by said setting means in a printing position.

2. Apparatus as claimed in claim 1 wherein said first and second surface portions are first and second surface halves; wherein said first and second angular positions are spaced 180; and wherein said first output means rotate said type head shaft and said type head 180 in one direction under the control of said cyclically operating means when said shift key means is actuated.

3. Apparatus as claimed in claim 2 wherein said first character types on said first surface halves represent lower case characters; wherein said second character types on said second surface half represent upper case characters; wherein said type head means has a normal lower case position in which said first surface half is in said operative position; and wherein said cyclically opcrating means turns said type head means to an upper case position,

4. Apparatus as claimed in claim 3 wherein said shift key means includes a key lever and a spring urging said key lever to a normal position of rest; wherein said key lever is manually operable for moving said key lever through an actuating position to a depressed position; wherein said key lever in said actuating position actuates said cyclically operating means to turn said type head means from said lower case position to said upper case position; and wherein said key lever when returned by said spring to said normal position of rest, moves again through said actuating position and actuates said cyclically operating means to turn said type head means 180 back to said normal lower case position.

5. Apparatus as claimed in claim 4 wherein said shift clutch has an engaged position connecting said drive means with said cyclically operating means and said first output means, and a normal disengaged position; electromagnetic means for placing said shift clutch in said engaged position, when energized; and switch means closed by said key lever when passing through said actuating position and connected with said electr0- magnetic means for energizing the same.

6. Apparatus as claimed in claim 1 wherein said cyclically operating means includes cam means connected with said rotary member for rotation; and cam follower means connected with said clutch means and operated by said cam means to move said clutch means to said first coupling position before said rack member turns said output gear.

7. Apparatus as claimed in claim 6 wherein rotary member has an inner gear ring; wherein said drive means include a drive gear, a clutch shaft connected by said shift clutch in said engaged position with said drive gear, and a pinion secured to said clutch shaft and meshing with said inner gear.

8. Apparatus as claimed in claim 6 wherein said clutch means include a clutch pin on said type head shaft; wherein said second output means of said setting means has a first coupling part forming part of said clutch means and being movably mounted on said type head shaft, said first coupling part having a first coupling cutout; wherein said clutch means further include a spring urging said first coupling part to said second coupling position in which said clutch pin is located in said first coupling cutout, wherein said first rotary output means of said shifting means has another coupling part having a second coupling cutout and forming part of said clutch means; and wherein said cam follower means move said other coupling part to said first coupling position in which said clutch pin is located in said second coupling recess, and outside of said first coupling recess.

9. Apparatus as claimed in claim 8 wherein said first output means is an output shaft coaxial with said type head shaft and having a portion forming said output gear; wherein said output shaft moves axially with said first coupling part to said first coupling position; and wherein said output gear is longer in axial direction than the corresponding dimension of said rack member so as to remain meshing engagement meshingengagement with the same during axial movement of said output shaft.

10. Apparatus as claimed in claim 1 comprising a platen; wherein said support means include a carriage movable in a writing direction along said platen, and a slide mounted on said carriage for movement transverse to said writing direction toward said platen; wherein said type head shaft is supported on said slide for rotation about said type head axis, and for movement with the same toward said platen; wherein said shifting means are mounted on said carriage; and wherein said type head shaft and said setting means are mounted on said slide for movement with the same in said second coupling position of said clutch means so that said selected type in said printing position is moved toward said platen for making an imprint.

11. Type head shifting apparatus comprising a support means; type head means mounted on said support means and including a type head and a type head shaft mounted on said support means for rotation about an axis, said type head having an annular surface concentric with said axis and having a first surface portion with first character types, and a second surface with second character types, said first and second character types being disposed along at least one circular line concentric with said axis, said type head means having first and second angular positions in which said first and second surface portions, respectively, are in operative positions for printing; drive means; shifting means including a shift key means, cyclically operating means connectable with said drive means under the control of said shift key means and having a first rotary output means, and a transmission including positively engaged movable members for accelerating and decelerating said first rotary output means in a sinusoidal movement so that said type head is gradually accelerated and decelerated when turning from one of said angular positions to the other angular position; setting means driven by said drive means and having a second output means; and clutch means controlled by said cyclically operating means to move between a first coupling position for coupling said first rotary output means with said type head shaft for rotating said type head from any one of said angular positions to the other angular position, and a second coupling position for coupling said second rotary output means with said type head shaft for rotating said type head until a selected type on the surface portion in said operative position is placed by said setting means in a printing position. i e

12. Type head shifting apparatus comprising a support means; type head means mounted on said support means and including a type head and a type head shaft mounted on said support means for rotation about an axis, said type head having an annular surface concentric with said axis and having a first surface portion with first character types, and a second surface with second character types, said first and second character types being disposed along at least one circular line concentric with said axis, said type head means having first and second angular positions in which said first and second surface portions, respectively, are in operative positions for printing; drive means, shifting means including a shift key means, cyclically operating means connectable with said drive means under the control of said shift key means and having a first rotary output means, and a transmission including a rotary eccentric first member rotatable by said drive means, a second member positively connected and driven by said first member along a straight path, said first output means including a rotary third member positively connected with said second member for being accelerated and decelerated in a sinusoidal movement, said shifting'means further including shift clutch means operable by said shift key means to connect said drive means with said eccentric first member so that said third member causes a rotation of said type head in a sinusoidal movement. 

1. Type head shifting apparatus comprising a support means; type head means mounted on said support means and including a type head and a type head shaft mounted on said support means for rotation about an axis, said type head having an annular surface concentric with said axis and having a first surface portion with first character types and a second surface portion with second character types, and first and second character types being disposed along at least one circular line concentric with said axis, said type head means having first and second angular positions in which said first and second surface portions, respectively, are in operative positions for printing; drive means; shifting means including a shift key means, and cyclically operating means connectable with said drive means under the control of said shift key means, said cyclically operating means including a rotary member having an excentric pin, and having a first rotary output means including an output gear; shift clutch means operable by said shift key means to connect said drive means with said rotary member for rotation so that said pin moves along along a circular path; a rack member guided for straight movement and having a slot receiving said pin so that said rack member is accelerated and decelerated in accordance with a sine function during rotation of said rotary member by said drive means and by said engaged shift clutch, said output gear meshing with said rack member; setting means driven by said drive means and having a second output means; and clutch means controlled by said cyclically operating means to move between a first coupling position for coupling said first rotary output means with said type head shaft for rotating said type head from any one of said angular positions to the other angular position, and a second coupling position for coupling said second rotary output means with said type head shaft for rotating said type head until a selected type on the surface portion in said operative position is placed by said setting means in a printing position.
 2. Apparatus as claimed in claim 1 wherein said first and second surface portions are first and second surface halves; wherein said first and second angular positions are spaced 180*; and wherein said first output means rotate said type head shaft and said type head 180* in one direction under the control of said cyclically operating means when said shift key means is actuated.
 3. Apparatus as claimed in claim 2 wherein said first character types on said first surface halves represent lower case characters; wherein said second character types on said second surface half represent upper case characters; wherein said type head means has a normal lower case position in which said first surface half is in said operative position; and wherein said cyclically operating means turns said type head means 180* to an upper case position.
 4. Apparatus as claimed in claim 3 wherein said shift key means includes a key lever and a spring urging said key lever to a normal position of rest; wherein said key lever is manually operable for moving said key lever through an actuating position to a depressed position; wherein said key lever in said actuating position actuates said cyclically operating means to turn said type head means from said lower case position to said upper case position; and wherein said key lever when returned by said spring to said normal position of rest, moves again through said actuating position and actuates said cyclically operating means to turn said type head means 180* back to said normal lower case position.
 5. Apparatus as claimed in claim 4 wherein said shift clutch has an engaged position connecting said drive means with said cyclically operating means and said first output means, and a normal disengaged position; electromagnetic means for placing said shift clutch in said engaged position, when energized; and switch means closed by said key lever when passing through said actuating position and connected with said electromagnetic means for energizing the same.
 6. Apparatus as claimed in claim 1 wherein said cyclically operating means includes cam means connected with said rotary member for rotation; and cam follower means connected with said clutch means and operated by said cam means to move said clutch means to said first coupling position before said rack member turns said output gear.
 7. Apparatus as claimed in claim 6 wherein rotary member has an inner gear ring; wherein said drive means include a drive gear, a clutch shaft connected by said shift clutch in said engaged position with said drive gear, and a pinion secured to said clutch shaft and meshing with said inner gear.
 8. Apparatus as claimed in claim 6 wherein said clutch means include a clutch pin on said type head shaft; wherein said second output means of said setting means has a first coupling part forming part of said clutch means and being movably mounted on said type head shaft, said first coupling part having a first coupling cutout; wherein said clutch means further include a spring urging said first coupling part to said second coupling position in which said clutch pin is located in said first coupling cutout, wherein said first rotary output means of said shifting means has another coupling part having a second coupling cutout and forming part of said clutch means; and wherein said cam follower means move said other coupling part to said first coupling position in which said clutch pin is located in said second coupling recEss, and outside of said first coupling recess.
 9. Apparatus as claimed in claim 8 wherein said first output means is an output shaft coaxial with said type head shaft and having a portion forming said output gear; wherein said output shaft moves axially with said first coupling part to said first coupling position; and wherein said output gear is longer in axial direction than the corresponding dimension of said rack member so as to remain meshing engagement meshingengagement with the same during axial movement of said output shaft.
 10. Apparatus as claimed in claim 1 comprising a platen; wherein said support means include a carriage movable in a writing direction along said platen, and a slide mounted on said carriage for movement transverse to said writing direction toward said platen; wherein said type head shaft is supported on said slide for rotation about said type head axis, and for movement with the same toward said platen; wherein said shifting means are mounted on said carriage; and wherein said type head shaft and said setting means are mounted on said slide for movement with the same in said second coupling position of said clutch means so that said selected type in said printing position is moved toward said platen for making an imprint.
 11. Type head shifting apparatus comprising a support means; type head means mounted on said support means and including a type head and a type head shaft mounted on said support means for rotation about an axis, said type head having an annular surface concentric with said axis and having a first surface portion with first character types, and a second surface with second character types, said first and second character types being disposed along at least one circular line concentric with said axis, said type head means having first and second angular positions in which said first and second surface portions, respectively, are in operative positions for printing; drive means; shifting means including a shift key means, cyclically operating means connectable with said drive means under the control of said shift key means and having a first rotary output means, and a transmission including positively engaged movable members for accelerating and decelerating said first rotary output means in a sinusoidal movement so that said type head is gradually accelerated and decelerated when turning from one of said angular positions to the other angular position; setting means driven by said drive means and having a second output means; and clutch means controlled by said cyclically operating means to move between a first coupling position for coupling said first rotary output means with said type head shaft for rotating said type head from any one of said angular positions to the other angular position, and a second coupling position for coupling said second rotary output means with said type head shaft for rotating said type head until a selected type on the surface portion in said operative position is placed by said setting means in a printing position.
 12. Type head shifting apparatus comprising a support means; type head means mounted on said support means and including a type head and a type head shaft mounted on said support means for rotation about an axis, said type head having an annular surface concentric with said axis and having a first surface portion with first character types, and a second surface with second character types, said first and second character types being disposed along at least one circular line concentric with said axis, said type head means having first and second angular positions in which said first and second surface portions, respectively, are in operative positions for printing; drive means, shifting means including a shift key means, cyclically operating means connectable with said drive means under the control of said shift key means and having a first rotary output means, and a transmission including a rotary eccentric first member rotatable by said drive means, a second member positivelY connected and driven by said first member along a straight path, said first output means including a rotary third member positively connected with said second member for being accelerated and decelerated in a sinusoidal movement, said shifting means further including shift clutch means operable by said shift key means to connect said drive means with said eccentric first member so that said third member causes a rotation of said type head in a sinusoidal movement. 